Hexagonal boron nitride type mold shell investment precoat for precision casting of magnesium alloy investment

Abstract

The invention discloses a hexagonal boron nitride mold shell investment precoat for precision casting of a magnesium alloy investment. The mold shell investment precoat takes silica sol as a binder and a hexagonal boron nitride powder body as a refractory raw material and comprises the following components in parts by weight: 100 parts of silica sol, 5-10 parts of deionized water, 0.100-0.15 part of bactericide, 400-600 parts of hexagonal boron nitride micropowder, 20-30 parts of polyvinyl acetate emulsion, 0.100-0.150 part of wetting dispersant and 0.050-0.100 part of defoamer. The mold shell investment prepared from the hexagonal boron nitride mold shell investment precoat disclosed by the invention has the characteristics that the reaction activity between the mold shell investment and a magnesium alloy is low; besides, hexagonal boron nitride is not infiltrated by a magnesium alloy melt, so a magnesium alloy casting is benefited; particularly, the mold filling of the magnesium alloy casting with the large-area thin-wall structural characteristics is benefited; in addition, other various performance indexes respectively meet the requirement of the magnesium alloy investment on precision casting.

Description

Technical field

[0001] The invention relates to a coating in the technical field of non-ferrous metal investment precision casting, in particular to a hexagonal boron nitride shell surface coating for magnesium alloy investment precision casting. Background technique

[0002] Magnesium and magnesium alloys, as the lightest metal structural materials, have the advantages of high specific strength / specific rigidity, dimensional stability, easy processing and forming, good thermal and electrical conductivity, damping and vibration reduction, electromagnetic shielding and easy recycling, so they are known as " 21st Century Green Engineering Materials". Magnesium alloy has become an important structural material in aerospace, automotive, electronic communication and other industrial fields. Magnesium alloy has strong casting process adaptability. Almost all casting methods such as sand casting, metal casting, gravity casting, lost foam casting, low pressure casting, investment castin...

Examples

Embodiment 1

[0025] In this embodiment, the preparation of the hexagonal boron nitride shell surface coating for magnesium alloy precision casting is achieved through the following steps:

[0026] 1) Add 100kg of silica sol, 5kg of deionized water and 100g of bactericide to the mixing machine, and slowly start the mixing machine for mixing;

[0027] 2) Add 600kg of hexagonal boron nitride powder of 200 mesh to 325 mesh gradually into the slurry mixing tank under stirring conditions, and assisted by manual stirring, so that the hexagonal boron nitride powder is completely dispersed in the silica sol and passed through ice The water machine controls the temperature of the paint so that the temperature does not exceed 26.7℃;

[0028] 3) Mix 20kg of polyvinyl acetate emulsion, 100g of wetting and dispersing agent, and 50g of defoaming agent in another mixing tank: first add the polyvinyl acetate emulsion, then slowly add the wetting and dispersing agent and defoaming agent, stirring to 3-5 minutes i...

Embodiment 2

[0032] In this embodiment, the production of the stainless steel precision casting mold shell surface layer is realized through the following steps:

[0033] 1) Add 100kg of silica sol, 7.5kg of deionized water and 125g of bactericide to the mixing machine, and slowly start the mixing machine for mixing;

[0034] 2) Add 500kg of hexagonal boron nitride powder of 200 mesh to 325 mesh gradually into the slurry mixing tank under stirring conditions, and assisted by manual stirring, so that the hexagonal boron nitride powder is completely dispersed in the silica sol and passed through ice The water machine controls the temperature of the paint so that the temperature does not exceed 26.7℃;

[0035] 3) Mix 25kg of polyvinyl acetate emulsion, 125g of wetting and dispersing agent and 75g of defoaming agent in another mixing tank: first add the polyvinyl acetate emulsion, and then slowly add the wetting and dispersing agent and defoaming agent. Too fast, otherwise it will cause the solution...

Embodiment 3

[0039] In this embodiment, the production of the stainless steel precision casting mold shell surface layer is realized through the following steps:

[0040] 1) Add 100kg of silica sol, 10kg of deionized water and 150g of bactericide to the mixing machine, and slowly start the mixing machine for mixing;

[0041] 2) Add 400kg of hexagonal boron nitride powder of 200 mesh to 325 mesh gradually into the slurry mixing tank under stirring conditions, and assisted by manual stirring, so that the hexagonal boron nitride powder is completely dispersed in the silica sol and passed through ice The water machine controls the temperature of the paint so that the temperature does not exceed 26.7℃;

[0042] 3) Mix 30kg of polyvinyl acetate emulsion, 150g of wetting and dispersing agent and 100g of defoaming agent in another mixing tank: first add the polyvinyl acetate emulsion, and then slowly add the wetting and dispersing agent and defoaming agent. Too fast, otherwise it will cause the solution...

Technical field

[0001] The invention relates to a coating in the technical field of non-ferrous metal investment precision casting, in particular to a hexagonal boron nitride shell surface coating for magnesium alloy investment precision casting. Background technique

[0002] Magnesium and magnesium alloys, as the lightest metal structural materials, have the advantages of high specific strength / specific rigidity, dimensional stability, easy processing and forming, good thermal and electrical conductivity, damping and vibration reduction, electromagnetic shielding and easy recycling, so they are known as " 21st Century Green Engineering Materials". Magnesium alloy has become an important structural material in aerospace, automotive, electronic communication and other industrial fields. Magnesium alloy has strong casting process adaptability. Almost all casting methods such as sand casting, metal casting, gravity casting, lost foam casting, low pressure casting, investment castin...

Examples

Embodiment 1

[0025] In this embodiment, the preparation of the hexagonal boron nitride shell surface coating for magnesium alloy precision casting is achieved through the following steps:

[0026] 1) Add 100kg of silica sol, 5kg of deionized water and 100g of bactericide to the mixing machine, and slowly start the mixing machine for mixing;

[0027] 2) Add 600kg of hexagonal boron nitride powder of 200 mesh to 325 mesh gradually into the slurry mixing tank under stirring conditions, and assisted by manual stirring, so that the hexagonal boron nitride powder is completely dispersed in the silica sol and passed through ice The water machine controls the temperature of the paint so that the temperature does not exceed 26.7℃;

[0028] 3) Mix 20kg of polyvinyl acetate emulsion, 100g of wetting and dispersing agent, and 50g of defoaming agent in another mixing tank: first add the polyvinyl acetate emulsion, then slowly add the wetting and dispersing agent and defoaming agent, stirring to 3-5 minutes i...

Embodiment 2

[0032] In this embodiment, the production of the stainless steel precision casting mold shell surface layer is realized through the following steps:

[0033] 1) Add 100kg of silica sol, 7.5kg of deionized water and 125g of bactericide to the mixing machine, and slowly start the mixing machine for mixing;

[0034] 2) Add 500kg of hexagonal boron nitride powder of 200 mesh to 325 mesh gradually into the slurry mixing tank under stirring conditions, and assisted by manual stirring, so that the hexagonal boron nitride powder is completely dispersed in the silica sol and passed through ice The water machine controls the temperature of the paint so that the temperature does not exceed 26.7℃;

[0035] 3) Mix 25kg of polyvinyl acetate emulsion, 125g of wetting and dispersing agent and 75g of defoaming agent in another mixing tank: first add the polyvinyl acetate emulsion, and then slowly add the wetting and dispersing agent and defoaming agent. Too fast, otherwise it will cause the solution...

Embodiment 3

[0039] In this embodiment, the production of the stainless steel precision casting mold shell surface layer is realized through the following steps:

[0040] 1) Add 100kg of silica sol, 10kg of deionized water and 150g of bactericide to the mixing machine, and slowly start the mixing machine for mixing;

[0041] 2) Add 400kg of hexagonal boron nitride powder of 200 mesh to 325 mesh gradually into the slurry mixing tank under stirring conditions, and assisted by manual stirring, so that the hexagonal boron nitride powder is completely dispersed in the silica sol and passed through ice The water machine controls the temperature of the paint so that the temperature does not exceed 26.7℃;

[0042] 3) Mix 30kg of polyvinyl acetate emulsion, 150g of wetting and dispersing agent and 100g of defoaming agent in another mixing tank: first add the polyvinyl acetate emulsion, and then slowly add the wetting and dispersing agent and defoaming agent. Too fast, otherwise it will cause the solution...